While no home can be entirely fireproof, the risk of fire can be significantly reduced through strategic design and material choices. These choices are often referred to as “hardening” a home against fire. DNM Architecture’s Deer Park house, located in a fire-prone area of Marin County, CA, is a prime example of hardening, employing ten key strategies to mitigate fire hazards effectively. The strategies include innovative framing, advanced fire suppression, building materials, and thoughtful landscaping, all of which collectively enhance the overall safety and resilience of the structure.
Steel Framing
One of the foundational strategies employed in the Deer Park house is the use of a modular steel framing system. Developed by BONE Structure, this system employs steel for all load-bearing walls, floors, and roof joists. Unlike traditional wood framing, steel provides a structural integrity that can withstand fire exposure for longer durations, thereby enhancing the overall fire resistance of the house. While steel is not entirely impervious to fire and can fail at extremely high temperatures, it offers a significant advantage by not contributing additional fuel to a fire.
Fire resistant steel framing – David Marlatt, AIA
Fire Sprinklers
Fire sprinklers are arguably the most critical feature for protecting a home from fire damage. According to a 2024 study by the National Fire Protection Association (NFPA), homes equipped with sprinklers experienced 89 percent fewer civilian deaths and 31 percent fewer injuries in structure fires from 2017 to 2021. By activating early in a fire’s development, sprinklers can extinguish or contain fires before they escalate into major conflagrations, significantly reducing potential damage and loss of life.
Noncombustible Exterior Wall Finishes
The exterior walls of the Deer Park house are clad in non-combustible materials: stucco and Nichiha cement fiber siding. These finishes not only protect the home but also deprive any encroaching fire of the fuel it needs to spread. By using materials that do not ignite, the house’s exterior provides a robust barrier against external fire threats, providing crucial time for occupants to evacuate and for emergency responders to arrive.
Managed Vegetation
Landscaping around the Deer Park house is meticulously managed to reduce fire risk. Large eucalyptus trees, known for being highly flammable due to their oil content, were either removed or topped. The remaining landscaping is strategically placed at least five feet away from the structure, creating a buffer zone minimizes the likelihood of fire spreading from vegetation to the house, further enhancing safety.
Type "X" Fire-Rated Walls
Inside the Deer Park house, all gypsum board is upgraded from the standard 1/2-inch regular gypsum board to 5/8-inch thick Type “X” for better fire resistance. For a small increase in material cost, every wall – including exterior walls – receives a one-hour fire rating. In conjunction with a suppressive fire sprinkler system, this upgrade significantly enhances the fire resistance of the home’s interior, offering occupants the maximum time to safely evacuate in the event of a fire.
No Soffit Vents
Traditional venting systems in roof cavities, while necessary for preventing moisture buildup, can also allow hot gases and embers to enter the building during a fire. The Deer Park house overcomes this challenge by using a combination of rigid and blown-in insulation, eliminating air cavities and the need for external vents on the eaves. This design not only reduces potential entry points for fire but also has the added benefit of added thermal efficiency, contributing to the home’s excellent energy performance.
Tempered Glass
All windows and doors in the Deer Park house feature tempered glass, which provides four to five times greater thermal resistance compared to traditional annealed glass. While primarily a safety feature to prevent injury in case of breakage, tempered glass also enhances the building’s ability to resist fire exposure, maintaining its integrity longer during a fire event.
Class A Roofing
The roofing material used in the Deer Park house is classified as Class A, the highest fire resistance rating available. Class A roofing does not contribute to fire spread, offering critical protection to the structure’s uppermost layer. This choice is essential in areas prone to wildfires, where flying embers landing on roofs can, and do, ignite less resistant materials contributing not only to destruction of property, but also to further spread of a major fire event.
All-Electric Systems
By eliminating the use of gas or propane, the Deer Park house reduces the risk of fire originating from fuel lines. Gas leaks, particularly after seismic events, are a common cause of house fires. By relying solely on electricity, the house mitigates this risk, contributing to a safer living environment.
Smoke and Fire Alarms
Finally, the presence of smoke and fire alarms in the Deer Park house is a standard yet vital safety feature. These alarms provide the earliest possible warning of a fire, offering occupants early warning and precious minutes to evacuate and contact emergency services. While commonplace, their role in enhancing fire safety cannot be overstated.
While no home can be entirely fireproof, the Deer Park house demonstrates that through thoughtful design and the integration of advanced safety features, the risk of fire can be significantly reduced. By combining steel framing, fire sprinklers, noncombustible materials, and thoughtful, focused design, DNM architecture created a home that is on the cutting edge of environmental performance, not only with regard to efficiency, but also uniquely suited to mitigate environmental hazards endemic to the California and the San Francisco Bay Area.
All images Jamie Leasure unless otherwise specified